Up to half of Canadian women using isotretinoin do not adhere to the current pregnancy prevention guidelines, suggests a new study.
Published in CMAJ, the study suggests up to 50 percent of women in Canada taking isotretinoin do not comply with the country's current guidelines for use of the drug, resulting in birth defects, miscarriages and pregnancy terminations.
Isotretinoin belongs to a class of drugs known as retinoids, and it is prescribed for severe recalcitrant nodular acne that has not responded to other treatments. The drug works by reducing the production of certain compounds that are known to contribute to acne.
Isotretinoin is known to increase the risk for pregnancy loss, birth defects - including craniofacial and heart defects - and death shortly after birth.
As such, the US Food and Drug Administration (FDA) launched the iPledge program, which aims to reduce fetal exposure to isotretinoin.
The FDA require that only prescribers and pharmacists registered to the program are permitted to prescribe and dispense the drug. Additionally, all patients must be registered to iPledge and complete an informed consent form before using isotretinoin.
Women of reproductive age must have two negative pregnancy tests before they can be prescribed isotretinoin under the iPledge program, as well as undertake a pregnancy test each month of drug use and use two forms of contraception, which should be recorded by their healthcare provider on a monthly basis.
Analysis of adherence to Canadian guidelines
While Canada - where the new study was conducted - has not adopted a program that is the exact equivalent to iPledge, there is a program in place that "requires informed written consent, two pregnancy tests with negative results before starting isotretinoin and two reliable forms of contraception during treatment," according to the authors.
But is this program effective? This is what lead author Dr. David Henry, senior scientist at the Institute for Clinical Evaluative Sciences (ICES), Canada, set out to investigate.
He and his team analyzed the health records for 59,271 women aged 12-48 years who were taking isotretinoin between 1996 and 2011. The women were from four provinces of Canada: British Columbia, Saskatchewan, Manitoba and Ontario.
During the 15-year study period, the researchers identified 1,473 pregnancies among the women, of which 118 (8%) resulted in live births. A total of 11 (9%) of these live births involved congenital abnormalities, according to the authors.
Medically induced abortion ended 1,041 of the pregnancies, while 290 were spontaneous losses.
The team identified a pregnancy rate of around four to six pregnancies per 1,000 women who used isotretinoin for a 3-month period.
25-30 percent of women did not fill birth control prescriptions
Overall, the researchers found that between 30-50 percent of women using isotretinoin did not adhere to current guidelines.
Only around 25-30 percent of women using isotretinoin filled birth control prescriptions while using the drug, despite guidelines stating that they must use at least two reliable forms of contraception during this time.
According to the researchers, their findings indicate a poor performance of the pregnancy prevention guidelines for isotretinoin use.
"Poor adherence with the Canadian pregnancy prevention guidelines means that Canada, inadvertently, is using pregnancy termination rather than pregnancy prevention to manage fetal risk from isotretinoin," says Dr. Henry.
The team says the findings support previous research suggesting that inadequate use of contraception is a leading reason for pregnancy during isotretinoin use.
"US studies have shown that the impact of the iPledge program also appears to have been modest in terms of increased uptake of oral contraceptives and reduced numbers of exposed pregnancies," say the authors, adding:
"It is clear from this experience and from studies in Europe that modifying contraceptive behavior in this setting is difficult.
Nevertheless, medical practitioners and patients must be constantly reminded of the risks of isotretinoin to the fetus and must adhere to the policy that mandates effective contraceptive measures."